Flywheel balancing machine



1 2 Sheets-Sheet l Dec. 29, 1931. T. c. vVAN DEGRIFT FLYWHEEL BALANCING MACHINE Filed Oct. 27, 1928 Dec. 29, 1931. T. c. VAN DEGRIFT FLYWHEEL BALANCING MACHINE 12 Sheets-Sheet 2 Fil-edOCt. 27, 1928 Dec. 29, 1931. T. c. VAN DEGRIFT 1,839,134

FLYWHEEL BALANCING MACHINE Filed Oct. 27, 1928 12 Sheets-Sheet 3 Dec. 29, 1931. T. c, VAN DEGRIFT FLYWHEEL BALANCING MACHINE 12 Sheets-Shree?I 4 Filed'OCt. 27, 1928 ff an? De- 29, 1931- fr. c. VAN DEGRIFT 1,839,134

FLYWHEEL BALANCING MACHINE Filed Oct. 27, 1928 12 Sheets-Sheet 5 DRILUNG gwuwntoc @Noz um? S Der; 29, 1931. T. c. VAN DEGRlF-r 1,839,134

- FLYWHEEL BALANCING MACHINE I y Filed Ot. 27, 1928 12 Sheets-Sheet 6 T. C. VAN DEGRIFT FLYWHEEL lBAIJANCING MACHINE Filed Oct. 27, 1928 12 Sheets-Sheet 7 Dec. 29, 1931.

Dec. 29, 1 931.

T. C. VAN DEGRIFT FLYWHEEL BALANCING MACHINE Filed Oct. 27. 1928 12 Sheets-Sheet 8 Zia S11/vanto@ www? Dec. 29, 1931. T, VAN DGRIFT 1,839,134

FLYWHEEL BALANCING MACHINE Filed Oct. 27, 1928 l2 Sheets-Sheet 9 Dec. 29, 1931.

T. C'. VAN DEGRIFT 'FLYWHEEL BALANCING MACHINE l2 Sheets-Shea?l lO Filedoct. 27, 1928 Dec. 29, 1931. T. c. VAN DEGRIFT FLYWHEEL BALANCING MACHINE Filed Oct. 27, 1928 12 Sheets-Sheet l1 lill/iff! Dec. 29, 1931.

T. C. VAN DEGRIFT FLYWHEEL BALANCING MACHINE 12 Sheets-Sheet, 12

FiledA oct. 27, 192s @511W @MQ Patented Dec. 29, 1931 UNITED STATES PATENT oFFl'cE THOMAS C. VAN DEGRIFT, OF DETROIT, MICHIGAN, ASSIGNOR TO GENERAL MOTORS RESEARCH CORPORATION, OF DETROIT, MICHIGAN, A CORPORATION OF DELAWARE FLYWHEEL BALANCING MACHINE Application filed October 27, 1928. Serial No. 315,509.

AUtilizing many of the principles that were exemplified in a crank shaft balancing machine application, S. N. 127 ,712, filed on or about August 6, 1926, by Caleb E. Summers jointly with the present applicant, but suitable for use in perfecting any of a wide variety of rotary elements, the present invention has been designed with special reference to the rapid ascertainment and correction of any unbalance in ily wheels or similar bodies having hubs.

Without implying any restriction, in actual use, to the balancing of units, such as fly wheels, whose mass may be largely concentrated in proximity to a single plane perpendicular to a geometrical axis, this machine, adapted both to the obtaining of information in regard to unbalance and to the correction thereof, will be described as provided with a special and standardized arbor, in-

cluding special centering means, with means for raising and lowering said arbor, and with novel means for effecting an actual removal of ascertained amounts of material from any imperfectly balanced fly wheels or other units,-such removal being effected, wholly or in greater part, while the units remain in the balancing machine and are favorably positioned for further test.

The mentioned material-removing means may include a special drill press organization having precision adjustment features which are believed capable of alternative uses; a novel chip-eliminator may be used therewith; and the present invention may include also the provision of novel means to facilitate the positioning, the support, and the removal of fly wheels or other units to be balanced,--the indicating means employed being either similar to or an improvement upon the corresponding means disclosed in the mentioned pending application and applicable, in either case, to alternative uses in ascertaining the behavior or properties of rotating bodies.

Typical embodiments of this invention may comprise an electric motor and a gear box or transmissionhousing secured at or near the top of an upright main frame or 5 0 post; and substantially parallel shafts, re-

spectively. serving as a main drive or spinning shaft, as a cam or control shaft, as an indicator shaft, and as a drill shaft may all extend downward from said housing,-upon which a control lever may be pivotally secured. Said housing may contain an hydraulic brake and may include means for a transmission of motion from said lever to said cam shaft, means for a transmission of motion simultaneously from said motor to the main drive shaft and to said indicator shaft, and means for an alternative transmission of motion to said drill shafts,shifts being eected in such sequence as to assure rapid and reliable operation of said machine.

Other obj ects of this invention, aiming at a maximum accuracy of balance in a minimum of time (its means and methodsbeing applicable to the balancing of various disc-like or other bodies) and numerous details of improvement upon or addition to the balancing'machine disclosed in the mentioned application, may be best appreciated from the following description of an illustrative embodiment of the present invention, taken in connection with the appended claims and the accompanying drawings.

Fig. 1 is a side elevational view.

Fig. 2 is a horizontal sectional view, taken substantially as indicated by the line 2-2 of Fig. 1, but with parts broken away.

Fig. 3 is a partial horizontal sectional view taken substantially as indicated by the line 3-3 of Fig. 1.

Fig. 4 is a partial front elevational view, taken substantially as indicated by the arrow 4 of Fig. 3.

Fig. 5 is a horizontal sectional view, taken substantially as indicated by the lines 5--5 of Figs. 1 and 6.

Fig. 6 is a vertical sectional view, taken substantially as indicated by line 6--6 of Fig. 5.

Fig. 7 is a general front elevational View, taken as from the right of Fig. 1.

Fig. 8 is a partial horizontal sectional view, taken substantially as indicated by the line 8*-8 of Fig 7. and showing details of a preferred wabble-limiting means adapted altersus v natively to permit or to prevent eccentric movement or wabbling of an arbor or a like central element during the rotation thereof.

Fig. 9 is a vertical sectional view, taken substantially as indicated by the line 9-9 of Fig. 8.

Fig. 10 is a partial side View, taken substantially as indicated by the arrow 10 of Fig. 7, and showing only a control lever and associated parts.

Fig. 11 is, for the most part, a vertical sectional view of a main spinning shaft, this view being taken substantially as indicated by the arrow 11 of Fig. 1, with parts broken awa Figs. 12 and 13 are respectively, a horizontal section taken substantially as indicated by the line 12-12 of Fig. 13 and the line 13-13 of Fig. 12.

Fig. 14 is a detail elevational view taken substantially as indicated by the arrow 14 of Fig. 13.

Fig. 15 is a separate elevational and diagrammatic view of a cam or control shaft manipulable by the lever which is separately illustrated in Fig. 10.

Figs. 16--21 are. respectively, plan 'views of various cams with which the cam shaft shown in Fig. 15 may be provided.

Fig. 22 is an elevational. detail view, with .parts broken away to a madian plane, showing a preferred type of adjustable bearing for a drill stem, as hereinafter described, this view being taken substantially in the broken plane 22-22 of Fig. 23.

Fig. 23 is a top plan view separately showing that main bearing element which is disclosed alsoin Fig. 22.

Fig. 24 is a partial sectional view taken substantially as indicated by the line 24.-24, Fig. 1,-`showing, in plan, certain features of drill press construction.

Fig. 25 is a detail view\taken substantially as indicated by the line 25-25 of Fig. 3.

Fig. 26 and 27 are respectively a side elevational view, with parts broken away, and a front elevational view of a preferred type of indicator mechanism.

Figs. 28, 29, 30 are respectively a top plan view, a longitudinal section and a transverse section of a preferred type of chip remover,

adapted to be used in conjunction with the mentioned drill.

General constmwton Although, as in the case of the now known and publicly used balancing machine described in the mentioned application, the body to be tested and/or corrected might have its axis disposed in any desired direction, a. base 20 (preferably provided with leveling screws, as suggested at 19, 19', Figs. 1 and 2) is herein shown as forwardly carrying a work-support in the form of housing 21, of somewhat complex character, and as rearwardly supporting a cast post or special column 22,- the latter being surzziounted by a rearwardlydisposed motor bracket 23 and by a forwardly disposed bracket 24, carrying a gear box or transmission housing 25; and one of the menti-oned brackets may have an iindicator drive housing 26 supported therefrom,-all of the mentioned parts being disposed favorably to the rotation of fly wheels or other work units W upon lvertical axes While carried by suitable parts positioned between said work supportl and said box.

From the housing 26, a guard tube 27, protecting an indicator shaft 27, may extend downward to any suitable indicator organization 28,-the latter being shown as also supported from post 22; and not only a main or work-spinning shaft 29 (preferably including universal joints 30, 30) to impart rotation to any work W, but a cam or control Ashaft 31 and a drill shaft 32 are shown as extending downward from the gear box 25,- said drill shaft being vertically adjustable through means carried by a guide block mounted upon the post 22.

A main control lever 34 is shown as pivoted at 35 upon the gear box 25; and said box is shown in Fig. 5 as provided, in its front and rear surfaces respectively, with bearings 36, 37 (protected respectively by a cap 38 and a gland 39) for a horizontal shaft 40,-this shaft being directly or indirectly driven from a. motor 41, carried by the bracket 23 and adapted, by means hereinafter described in detail, either to impart rotation simultaneously to indicator shaft 27 and to main shaft 29 or (upon a shifting of lever 34 and a consequent discontinuanc'e of rotation of shaft 29) to energize the drill shaft 32,-the latter being positioned favorably to the removal of an indicated quantity of material from an indicated portion of the periphery of the fly wheel or other work W.

Through means hereinafter described, manipulation of a` work-positioning handle in the form of a forwardly projecting arm 42 may operate means which assist in an initial positioning of, and/or in the support of, the work W above the block 2l; a standardized arbor 43, preferably provided with some suitable means for supporting from below and very accurately centering any work W thereon, may be raised, subject to an interlocking control, relatively to the main shaft 29, by or upon a manipulation of a j ack-operating lever 44; and the raising and lowering of drill point 45, conditionally rotated by shaft 32, may be accomplished by manipulation of an addi- 1 tion of typical mechanisms b which said operations may be satisfactori y eifected.

Work positioning and non-rotary supporting means As suggested in Fig. 7, conveying or rollercarrying tables T, T, may advantageously be so disposed, at the sides of the balancing machine herein described, as to obviate manual lifting in the transfer of fly wheels W thereto or therefrom; and the block 21, shown as comprising a substantially cylindrical lower section 21a and a rectangular upper section 215, may be provided with not only a comparatively large central opening 47 (through which the standardized armor 43 can be raised and lowered) and with an annular camv plates 48, manipulableby the arm 42, but with any desired set of rollers 49,-the latter being shown as disposed at substantially the same level as similar rollers 49a and 49?) carried by conveyor tables T, T.

Although preferably so shaped as to bring connected with a slidable rod 71.

its free end to a desired level above a slot 50 through which it extends, the arm 42, shown as secured to cam plate 48 by a bracket 42, is not intended to serve as an ordinary crank, being'designed, by causingl an engagement of cams 51, 51"with pins 53, 53 (upon the shifting of said arm toward the right) to elevate Work-stopping and centering pawls or dogs 52, 52, or (upon a shifting of said handle toward the left, in preparation for a drilling operation which occurs, if at all, only after intervening operations) to cause engagement of cam surfaces 54 with rollers 55, and thereby to elevate work-levelers of platen elements 56,-the dogs 52, 52 and the work-levelers 56 being otherwise depressed (during spinning operations and handling operations) below the tops of rollers 49,-as by means of springs, 57, 58, surrounding interposed slidable elements 59, 60 of said pins and said work-levellers.

As more fully detailed below, the dogs 52, 52 and work-levelers 56 are constructed and disposed with special reference to diameter and configuration of the work W and to its adequate support,-one or all of 'said worklevelers serving as a press plate or platen, during such drilling operations, if any, as may be deemed requisite in view of observations of indicator 28, as made during a spinning which precedes the elevation of said work-levelers.

Arbor elevator 0r jack Regardless of the specific construction of the means, if any, employed to facilitate the positioning of work units W, assuming that said units are not provided with integral shafts, suitable means, operated or controlled by the lever 44, may be employed to manipulate a standardized arbor 43, or its equivalent, relatively thereto,-the illustrated arbor be- 'with such securing means ing shown as provided not only with a centering organization 61, adapted to fit within a fly wheel opening, or the lilTA Yut with roller-engageable, sections 62, L., respectively disposed above and belowl said centering organization, with a torque-transmitting head or chuck 63, for connection with the main shaft 29, and with a tapered lower end 64, adapted to be held by, but easily removably from, some interiitting and vertically slideable-socket member 65, comprisedin an elevating organization controlled by said lever.

For example, in view of the recognized facility of control of hydraulic and especially of pneumatic devices, a valve 66, manipulable from lever 44 by means such as a link 67 and a valve arm 68, may be used to control admission of air (according as said lever is elevated or depressed) from a pressure pipe 69, to actupon one or the other of opposite sides of a. piston (not shown) movable Within a Ross air cylinder 70, or the like, and

In preference to disposing the airmanip ulable rod 71- vertically and directly below the arbor-receiving socket member 65, space may be saved by providing the cylinder (not shown in full detail) as to permit of some longitudinal adjustmentthereof, and fixing a frame 72 above a suitable well 7 3 in a bottom section 20a of base 20; and transmission means, subject to an interlocking control, may be so employed in connection with rod 71 and fram'e 72 as to provide for the manipulation of arbor socket 64,-to raise the same when a work unit W has been approximately positioned and to lower the same (to a level favorable to the horizontal removal and re.- ception of units W) after the requirements of accurate balancing have been ascertained and/or met. For example, an upper or main section 206 of the base 2() being shown as provided with a lateral opening 74 (illustrated in Fig. 7 as provided with a door 7 5 having a knobk 76) the frame 72 may be adapted to carry not only a gear 77, engageable by a rack 78 on rod 71, and a sprocket 79 driven from gear 77 by gear 80 (shafts 81 and 82 being shown as parallel) but also an upper sprocket 83, mounted upon a separate bracket 84,-Which may be retained by shoulders 85, although subject to an adjusting screw 86; 'and a suitable chain 87, extending over the sprockets 79 and 83, may carry not only a socket-receiving bracket 88 but also any desired counter weight 89.

The frame 72 is shown as carrying also .a bracket 90, to guidev an interlocking pin 91, whose retraction from engagement with socket-receiving bracket 88 (in such manner as to permit initial elevation of said socket and bracket, together with the mentioned arbor) may be dependent upon the position of a jack-interlocking cam 92 upon the control or cam shaft 31; and it may have been noted, in connection With Figs; 3 and 4, that a slidable pin 93 is so shaped and positioned as to render the vertical manipulation of the air valve rod or link 67 by lever 44 or its equivalent (a pin-and-slot being suggested at 94, Fig. 1) dependent upon a specific. rotative position of a cam 95,-shown as secured on said control shaft at some distance above a lower bearing 96. Said control shaft may carry also interlocking cams 97a, 97?),- the shapes and positions and relationships V thereof to pins 97a, 975 being such as to render manipulation of arm 42, to rotate cam plate 48, conditional upon a specific position ing of shaft 31, or vice versa; but the full significance of the control features last referred to may be best understood in connection with a statement of operations hereinafter provided.

It will be understood that the depth of the well 7 3 .and the proportions of the mentioned parts are intended to be such as to adapt any standardized arbor 43, Whatever may be the details of its structure, to bel depressed below the level of the rollers 49 both during an initial Work-receiving period (wherein the dogs 52, 52 are so elevated as to aid in the correct positioning a Work unit W) and durn ing a final Work-removal period; that the length and the range of vertical movement of the arbor 43 are intended to be such as to facilitate the coupling of the same, When a Work unit has been centered and secured thereonl` to the main or spinning shaft 29; that the range of movement and spacing of the work-levers 56 is intended to be such as to adapt the latter to be elevated, by means such as the rollers 49, at least during any desired material-removingoperations in which one or more thereof may serve as a press plate or platen; and that the dogs 52, 52 and the levelers 56 are alike held depressed dur ing spinning operations, executed for the ascertainment of any unbalance; but it will be obvious that various changes in design may be found advantageous in adapting this machine to the balancing of fly' Wheels 0r other work units 1V of special design or cast integral with shafts.

0am or control shaft .a and said upper-plate cams (concealed in Fig.

1 by an upper plate-carrying or feeler-carrying bracket 100) being best shown in Figs. 8, 9, 15, and 20.

The cam shaft or control shaft 31 is shown in Fig. 5 and 6 as provided, Within the gear box 25, with a brake-operating cam 101 and With clutch-operating cams 1020i, 1025; and also With a bevel gear 103,-preferably disposed immediately above or below a twopart bearing arm comprising a flanged main element 10411 and a complemental element 1045, retained by means of bolts or screws 105.

Gear 720m and main drive Referring now more particularly to Figs. 5 and 6, the shaft 40 of the motor 41, mentioned as supported by bearings 36 and 37, may be constantly rotated in the direction suggested by arrow 110; and said shaft 40 is shown as carrying not only a main clutch block 111 but Worms 112 and 113 upon respective counterpart clutch blocks 114 and 115,-the clutch block 111 being slidable and shown as provided with an intermediate fork-receiving groove or channel 116. The

upper end of drill shaft 32 is shown as provided With a gear 117 engaged by an idler 119, on a short shaft 118,-said idler being interlocked or rigidly connected With a Worm gear 120. The latter may be in constant mesh With the Worm 112; and the Worm 113 may similarly remain constantly in mesh with both a gear 121 (upon an upper end or section 29Y of the main Work-spinning shaft 29) and With an additional gear 122,-the gear 122 being show'n as mounted upon a short vertical shaft 123, carrying a small bevel gear 124 and as adapted, through the intermediation of a shaft 125, provided with beveled gears 126 and 127, conditionally to impart rotationto a gear 128. The latter may be so secured upon the upper end of the mentioned indicator shaft 27 as to permit of an initial rotation and adjustment, to compensate for some lag in the action of feeler and indicator elements, hereinafter referred to.

Clutch, braise, and gear-box lubrication The clutch block 111 is shown as shiftable to and from an intermediate position of complete disengagement by means of a clutch lever 129, this lever being p ivoted u on a stub shaft or bolt 130 and comprising ork arms 131, 131 (engaging in the clutch-groove 116 in the clutch block 111) andialso a cam roller arm 132,-the latter being engageable by the mentioned cams 102a, 1025 on shaft 31; a brake-control lever 133, pivoted at 134, may

- be provided with a roller or equivalent member 135, adapted to co-operate with brake cam 101; the shaft 125 is shown as carried by a bearing plate 136 (optionally integral with the housing 26) and by a'bearing arm 137 ,-said plate and said arm being both supported from boX 25; androne of the shafts 29, 1237 or vided with a brake of some suitable type,- manipulable through the mentioned cam 101 and lever 133. lFor example, incidentally providing means for the circulation of a lubricant reaching to a predetermined level within the gear box 35, a gear pump which comprises gears 138, 138 .and a fixed pump body element 139 (shown as integral with a bearing-and-closure plate 140, supporting bearings 141 anda cap 142) may be employed for a braking ei'ect,-gear 138 being shown as compelled by lugs 143 to rotate with shaft 123.

Assuming the gear box 25 normally to contain lubricating oil up to some such level as that roughly indicated by the line 144, Fig. 6, the described pump, or its equivalent, may be provided with a submerged inlet connection 145,-shown as equipped with a strainer 146; and an outlet pipe 147, 147, leading from said pump, may be provided with a valve 148,-capable of being opened, through the agency of cam 101 and brake lever 133, by means such as a link 149, engaging a valveoperating arm 150; a remoter portion 147 of the mentioned pipe may be provided with any desired branches,such as arevsuggested at 151 and 151', Fig. 5, for the ever the valve 148 is opened and the worm 133, or its equivalent, is rotated; and, to determine a maximum braking pressure, a relief valve (not shown) may be suitably inserted in pipe 147 or'its equivalent.

Optional swinging support for drill shaft To avoid unduly complicating Fig. v5, but few parts of a complete lubricating system are therein shown; and a like consideration has excluded from said figure the details of a special bearing construction preferredl for use at `the yupper end of drill shaft 32. It is nevertheless thought proper, calling attention to dotted line152 in said figure as indicating an optional arcuate opening, hereto comment that the retention of lubricating oil in box 25, or its equivalent, is not incompatible With the use of means permitting such adjustment of the drill shaft 32 relatively to the idler shaft 118 (as a center of rotative adjustment) and tothe main or .spinning shaft section 29 f as to permit a removal of material, by lrota- 125 may advantageously be pro- 118 but at a variable distance from shaft 29,

delivery of lubri-y cant to the various mentioned bearings whention of said drill shaft, at various radial distances from an axis of rotation common to the last-mentioned shaft and the arbor 43 and any work W thereon,as may be advantageous in balancing fly wheels, or the like, having different diameters; but preferred details of the construction here referred to may be best understood from Figs. 22 and 23.

As shown in the figures last referred to, a special bearing element 153 may be pivoted upon idler shaft 118, or upon a bearing sleeve 154 provided therefor, and may thereby guide at a uniform lateral distance from shaft etc.) the drill shaft That portion of the bottom of box 25 through whichdrill shaft 32 extends, or a plate secured to said box, may be provided with a flat inne-r or upper surface 155, and optionally also with a bearing element such as the mentioned bearing sleeve 154,-the latter being adapted to constitute or to support the short shaft 118, mentioned as carrying idler 119 vand worm 120; and the special bear- 1n ongly a plate 157, having a co-operating Hat and smooth lower surface and provided with arcuate slots 158, 159 (adapted to receive clamping screws or bolts 160) and a circular opening 161 for shaft 32, but also parallel cylindrical bodies 162 and 163,-the latter being adapted respectively to receive a sleeve containing 'shaft 118, and a bearing organization 164 for the drill shaft 32. Idler 119 and worm gear 120 are shown as interlocked but nevertheless freely rotatable together relatively to shaft 118 gear 117 is shown as keyed to drill shaft 32; and glands 165, 165 are shown as respectively surrounding the cam shaft 31 (Fig. 6) and shaft 32; but many of the foregoing details are here included only for the sake of completeness, being'entirely optional.

Work-spinning shaft ami arbor 'above referred to as comprising the upper section 29', within the box 25, universal joints 30, 30', and torque-transmitting head 63, is shown in Figs. 1 and 11 as including a scale carrying section 164, between the section 29 and the upper universal joint 30,-the unversals 30 and 30 being respectively separable, upon withdrawal of taper pins 165@ and 165a and 16'5, from sections 29a and 29?); and the arbor-receiving head 63-may be substantially similar to that shown in the mentioned prior application,-its construction adapting it to be tightened or loosened by rotation of a collar 166. v

Complete separation of the sections 29a, 295 may be obviated by means such as a head 16,7, optionally adjustable, adapted to engage a shoulder or other internal stop 168; and it element 153 is shown as comprising not ected after a s innin indication of unbalance and in preparation of a drilling operation, by manually grasping and so rotating the work W, and parts movable therewith, as to shift the scale 17 0 consistently with a reading previously given by the indicator 28, or

its equivalent, during the spinning opera tion; but'the capabilities here referred to may be best understood in connection with preferred details of construction of the arbor 43,--adapted both the center and rotatably to connect any work W with the shaft 29, or its equivalent.

Wark-ceteng arbor construction In connection with Figs. 12-14 inclusive, it should be recalled that separate roller-engaging arbor sections, such as that shown at 62 as comprising an accurately tting and hardened shell retained upon a main arbor body element 171 by means of threaded collars 172, 173, are preferably provided both above and below the work-centering organization 61 of the arbor 43; and said workcentering organization may include a replaceable work-carrying element 174, comprising a cylindrical part 174 anda flange 174" the outside diameter of said cylindrical part being preferably but slightly larger than the shaft-opening in the hub of any wheel or work W that may be carried and spun thereby. This flanged element 17 4 is shown as retained between a shoulder 175 and a threaded collar 176 and as provided with laterally extending a ertures 177 for Work-centering pins 178. he apertures 17 7 may coincide with corresponding apertures 17 7 in the arbor body 171; and said body isA shown as provided with a longitudinal bore 179, containing a pin-advancing conical cam 180, formed of hard material.

The pins 178, also accurately formed of hard'material and shown as having rounded ends, are intended to be very exactly equal to one another in length; and they may be retained against accidental loss by means such as balls 181, adapted to engage channels 182 in said pins,said balls being shown as' resiliently pressed thereto by means of springs 183 retained in bores 184 by plugs 185; the pin-advance cone 180 is shown as movable by a stem 186, provided with` guide sections 187, 188, 189,-which are intended accurately to fit within the bore 179 or within special guides 190, 191, suitably positioned therein; and the stem 186' may be manipulated, to advance and retract the cone 180, by means such as a threaded body 192, seated in the main body 171 and shown as provided with a milled head 193,-said body preferably so receiving a stud 194, on stem 186, as

to advance or retract the same, according to lposed thereon, and that pins 178, or their equivalent, are intended for a centering rather than a supporting effect. To adapt the flange 174 to the supporting purpostl referred to, and in view of common imperfections in the hubs of fly wheels and the like, point-to-point supports therefor may be provided upon said flange,-as by the insertion and careful grinding, preferably in plan. of suitable hard studs 195; and said flange may, if desired, be provided with vertically hilable and resiliently supported additional vlc` ments, such asl pins 196, respectively movable by leaf springs 197,-said pins being capable of serving, inter alia, to guard the studs 195, to function as clutch elements and/or to facilitate the removal of any work unit W whenvoperations thereon are completed. e

As in theformer inst-ance referred to, the chuck or head 63, on ning shaft 29, is shown as provided with a dog or dogs 198,-advanced by rotation of a cam element or elements 199, optionally integral with a milled or other collar 166; an upper portion of the arbor body 171 is shown as provided with dog-receiving slots 201 and it will be understood that the conca-vity 202 Within the chuck 62 or its equivalent is intended to be such that, when a work unit W has been dulycentered by adjustment of the milled head 193, said head and parts immediately therebelow may all be received with- 1n said chuck,-in readiness for both a spinning operation (upon a lowering of the mentioned dogs 53) and any subsequent drilling or other metal-removing or metal-adding operations (executed upon a subsequent elevation of the work levelers 56) as may be required to assure the desired perfection of balance. I

Means having the indicated general character being preferably employed to center the work W upon any arbor 42 in readiness for splnning and for subsequent operations effected by proper manipulation of the lever the lower end of spin-` 34, the arbor-centering or restraining and/or feeling and indicating means used therewith may be either quite different from or generically similar to corresponding means illustrated in the mentionedV prior application,-improved but similar means being herein described.

Arbor-restraining and feelin-g 'means organization, controlled through cams 98a and 985 on shaft 31, may be so entirely similar in principle and in mode of manipulation to that shown in Figs. 8 and 9 as to require no separate illustration,#the expediency of providing a separate feeling arm vin connection with said lower arbor-restraining organization naturally depending somewhat upon the distribution of mass in the work units W constituting a particular batch to be tested and/or balanced.

Bracket 100 will be seen to comprise, in addition to a rugged back or attachment section 1005` and vertically-extending, 4 forwardly-diminishing side webs 1005, the irregularly rounded area referred to as upper plate 1000; and thel latter is shown as provided not only with an ample central opening 204, for the upper roller-engageable section 62 of-arbor'43, but with an arcuate opening 205 for drill shaft 32 or a downward extension thereof, with an opening for cam or control shaft 31, and with additional openings corresponding to hollow trunnions or bearing sleeves 206, 207,208. The latter are accurately made, to serve as or to carry pivots for both a lower set of roller-carrying arms 206a, 2070, 2085, and a corresponding upper .set of arms 2065, 2075, 2085,-said upper arms being shown as respectively provided with gear sectors 2060,- 2070, 2080, all engaging an identical ring gear 209; and one of the mentioned sector-carrying arms is shown as having associated therewith a control arm 210, carrying cam rollers 211, 212, for engagement by the cam 0r cams 99a, 995, upon the control shaft 31. Rollers 2060i. 207 d, 2080?, upon arms 2065, 207 a, 2080 (preferably chrome-plated to resist wear) are adapted t0 engage section 62 of arbor 43 (which may be similarly plated) and precise adjustment of the control arm 210 may be effected by means such as screw 213, v213', shown as threaded into an extension 214 of arm 2085 andas adapted to engage a suitable abutment such as a clamping screw'219, upon arm 210.

Upper arms 2065, 207 5, 2085 may be integral with outer bearing elements 2060, 207 e, 2080, respectively rotatable upon bearing sleeves 206, etc.; lower arms 206a, 2070, 2085 may be separately carried by pivot bolts 2067, 207f, *20S/i," rotatable within said bearing sleeves; and resilient means such as adjustable tension springs may tend constantly to 'draw the rollers 2060i, 2070i, 2086i together.

Plate 1000 being provided with additional openings 206g, 207g, 208g, the movement 0r play permitted to said lower arms relatively to corresponding upper arms may be varied by means such as oppositely extending pairs of screws 2065, 2075, 2085 co-operating with lugs or studs 206i, 2072', 208z',-it being relatively immaterial, except as to convenience of access, whether said studs (shown as provided with flat lateral faces, relatively inclined) are carried by the lower arms, as shown, or vice versa. y

The various relationships and adjustments above referred to will be understood to be such that arsuitable partial rotation of the control shaft 31, as effected by means such as the lever 34, may cause the rollers 2060K, 2070?, 20803, either uniformly to close in upon and to steadyl one end of the arbor 43,- during its l rotation, or to so releasev the same as to permitsuch separate movement thereof'as may result from any unbalance,-the latter condition prevailing during the use of said rollers as parts of a feeler organization.

In order to adapt the mentioned roller-carrying arms to operate the indicator 28, or its equivalent, the arm 208er, for example, may

be rigidly or otherwise connected with an indicator-actuating arm 215; and, all of the arms 20601 207 a, 2085, being capable of rocking movement within the limits permitted by adjustment of screws 2065, 2075, 2085 and by the rotative position of cams 1095, 1095, said rollers may function, at times, as sensory parts of a feeling or pressure-responsive system adapted to respond to Wabbling of arbor 43 and to transmit motion to interior parts of the indicator 28, or its equivalent.

Rollers 206d, 20707, 2080i, are shown as yieldably drawn inward by resilient means in the form of tension springs 206,7', 207y', 208,7', adjustable by screws 2065:, and 207 5, and 2085: extending through threaded bodies 206Z, 207 Z, and 208Z, the screws 206k, and 207 5 being provided with milled or knurled heads 206mJ and 207m. Plate 1000 may be additionally apertured, as at 2065, 2075, and 2085; and some or all roller-carrying arms may be provided with damping means extending thereto. This is herein done by additionally and yieldably connecting each lower arm with the arm thereabove by one of three offset fingers 20629, 20737, 208p,-the mentioned damping elements being so interposed that, although pressure impulses due to eccentric motion or wabbling of arbor 43, or to like cause, may be reliably transmitted therethrough, said rollers shall not otherwise vibrate or chatter.

The fingers 206,6, 2072 208g?. are shown as respectively integral with additional arms 2066', 2076', 2086', disposed at fixed angles relatively to arms 2066, 2076, 2086; and

vdamping organizations in the form of rubber i blocks 206g, 207g, v208gare'shown as so interposed between fingers 20610, 20712, 20812 (respectively carrying sockets 2061', 2077", and 2087', through which extend clamping bolts 206s, 207s, 208s) and correspondingly rollercarrying arms 206a, 207a, 208a (carrying sockets 2067-', 2077*', 20871', through which extend clamping bolts 206s', 207s', 2088) that, although the arms 2066', 2076', 2086 are compelled to move equally (because geared together in the described manner) the rollers 206d, 20706, 2086i are notrestricted to synchronous and or equal movement. Drawn inward by springs 206g, 207g, 208g, it will be seen that rollers 206a, 207a, and 208a are So related that any outward pressure applied to (say) roller 208a (by reason of e. g., any tendency of shell 62 or arb-or 43'to move as an eccentric) may not only swing the actuating arm 215 backward, to a corresponding degree, but may also'tend, rthrough damping element 208g, arm 2086', arm 2086, gear sec.- tor 2080, ring gear 204, and parts movable by said gear, slmultaneously and yieldably to apply additional inward pressure to rollers 2066 and 2076,-assuring the retention of the same in non-chattering contact with arbor shell 62, or its equivalent. It is, however, for a locking efect that gears are here used.

A substantially circular and suitably apertured removable cover plate 1000i, adapted to engage a machined area 100e at the edge of plate 1000, may protect mentioned movable parts; and, to facilitate adjustment of screw 208k, or its equivalent l(whether employed primarily to predetermine the pressure of application of roller 208a or as a means of zero-setting or zero-correcting the indicatoractuating arm 2 15, or for both of these purposes) an extension of said screw, shown as rotatable in bearing elements in 216 and 100f, may be provided with an accessible handle or head 217.

When the mentioned parts are in proper proportion and adjustment, assuming that,

. for example, some net excess of materialat an angular distance of 25 from an assumed zero (said zero optionally corresponding to that radial plane of a ily-wheel W which passes through drill 45 as said wheel may happen to be disposed when the scale 170, or its equivalent, reads zero) the consequent tendency of arbor 43, when rotating as an eccentric, to press upon the roller 208@ once during each revolution may be used in so operating any properly constructed indicator 28 that the readings of the latter reveal both where and how much material must be removed from the heavy side of the work W in order to obtain substantial perfection of balance; and one improved type of indicator will accordingly be next described. In this connection it may be pointed out that the line of application of what may be referred to as maximum wabble-pressure lies, when instrumental constants are properly compensated and operations are conducted at an optimum R. P. M., about opposite (i. e. at about 180o from) any net excess of mass in the work W,said excess being initially assumed to lie in, or very near, a central horizontal plane. In the suggested case, the crest of the wave of lateral pressure may thus come at an angle of 105 from the assumed zero of the fly wheel; but the connections and adjustment of the indicator 28 may nevertheless be such as to give the reading 25 upon the indicator 28,-this being the position to which scale 170 should be brought in Indicator structure amd operation Indicator 28, or its equivalent, may be supported wholly or in major part by means such as a bracket 218,-shown as carried by post 22 and as adapted to serve as a support for gearing whereby suitable rotation may be imparted to a mirror or set of mirrors 219, comprised in said indicator.

When intended to be used as herein described, the indicator 28 may comprise, within a housing 220, not only the mentioned rotating mirror (whose sides or faces may correspond in number with a speed-reduction ratio between shafts 29 and 27 '-this mirror being octagonal in cross-section) but also an oscillable concave mirror 221 (movable by any suitable indicator-actuating element 215) a light source 222, and an arcuate window opening 223 having therein suitable particylindrical graph-receiving or graph-displaying translucent element 224,-a ray-restrictive element 225 and a background illumination window containing color-di'usion screen 226 being optionally provided in or carried by an inner wall or walls 228, dening a lamp compartment 229.

The curvature of the oscillable mirror 221 is preferably such that an unvarying ray which it receives through an aperture 230 in the ray-restrictive element 225 (shown as retained in an adjusted position by a slotted plate 231 and clamping screws 232) shall be approximately focused, as reected from the rotating mirror 219, in the plane of the graphdisplaying element 224,-this being secured at a uniform radial distance from the axis of 

